AB0335 THE FREQUENCY OF SWITCH FROM ANTI-TNF ORIGINATORS TO BIOSIMILARS AND THE CLINICAL OUTCOMES – REAL-WORLD RETROSPECTIVE STUDY IN FOUR ITALIAN CENTRES
Authors: F. Atzeni, M. Bardelli, P. Moscato, M. Giallanza, D. Birra, F. Pistillo, A. Carletto
Journal: Annals of the Rheumatic Diseases (2022)

Background Biologics, such as tumor necrosis factor inhibitors (TNFi), are highly effective in the treatment of inflammatory arthritis, i.e., rheumatoid arthritis (RA), psoriatic arthritis (PsA), and axial spondyloarthritis (axSpA). The importance of collecting real-world evidence data on switching patients from an originator to a corresponding biosimilar is well recognized in the field (1). Objectives The aim of the study was to evaluate the frequency and clinical outcomes of the switch in patients with RA, PsA and axSpA to determine whether a switch could cause a reactivation of the disease. Methods We searched electronic patient’s records in four Italian centers for consecutive adult patients treated with TNFi for RA, PsS and axSpA. For these patients, we extracted data on age, gender, age and diagnosis and disease duration, the history of a switch from a TNFi originator to a biosimilar, and swollen joints, tender joints, global health, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP). We calculated composite indices of disease activity, DAS28-ESR, DAS28-CRP, CDAI and SDAI, at baseline, and at 3 and 6 months of follow-up. Response was calculated as the difference between DAS28 at baseline and at 3 or 6 months and stratified into good, moderate, no response according to EURAL response criteria. Chi-square test was used to assess if lower response rates were encountered in the switch versus no-switch groups. The Generalized Linear Regression Model was used to study the relationship between DAS28-ESR/CRP responses at 3 and 6 months and DAS28-ESR/CRP, age, sex, smoke or switch at baseline as predictors. Results We identified 195 patients; cohort’s descriptive statistics are given in Table 1. A total of 140 (74%) patients were switched from adalimumab to a biosimilar. At 3 months after the switch, 25 (19%) and 17 (13%) of patients were defined as good responders, 48 (36%) and 41 (31%) as moderate responders and 61 (46%) and 76 (57%) patients as non-responders, on DAS28-ESR and DAS28-CRP, respectively. At 6 months, 28 (24%) and 22 (19%) of patients had a good response, 29 (25%) and 32 (28%) – a moderate response and 59 (51%) and 62 (53%) patients did not respond, on DAS28-ESR and DAS28-CRP (Figure 1), respectively. The results of the Chi-squared test indicated no difference in the frequency of good/moderate/no response at 3 and 6 months on DAS28-ESR/CRP between patients switched and not. There was a significant association between age and DAS28-ESR/CRP response at 6 months (p&lt;0.001 and p=0.025) respectively. Table 1. Patients characteristics Variables N = 195 1 Age Mean (SD) 55.05 (13.95) Median (IQR) 57.00 (48.00, 64.00) Minimum 18.00 Maximum 86.00 (Missing) 6 Sex F 120 (62%) M 74 (38%) (Missing) 1 Smoke no + ex-smokers 150 (79%) yes 39 (21%) (Missing) 6 ANTI-CCP neg 130 (75%) pos 40 (23%) (Missing) 25 1 Mean (SD), Median (IQR), Min, Max or Frequency (%) Conclusion About three quarters of the patients included in this study underwent a switch from an originator to a biosimilar TNFi. The response rates were similar in those who did and who did not undergo a switch. The switch did not determine a reactivation of the disease. References [1]Atzeni F et al. Efficacy and Safety of Biosimilar and Originator Etanercept in Rheumatoid Arthritis Patients: Real-Life Data. Isr Med Assoc J 2021;23:344-349. Disclosure of Interests None declared